Help me with this interval identification

lincolnblue

My theory knowledge is rubbish so I realise this might be basic but I'm getting stuck,

I've come up with a riff in the key of D major which is D, F, C, D

D is the 1 or the root. E is the 2 and F# 3 so would an F major be a flat 3? Then the C, is that a flat 7?

It's just bugging me!

merlin

F natural in the key of D is a minor 3rd. C natural is a minor (flatted) 7th. Talking the notes and intervals. 

If you're talking about the chords being related to each other, then that's a whole different question. 

viz

Yes, you are playing in D major (because the D chord is major), but, as is common in blues/rock, you are also allowing major chords that are outside D major and based on the notes that are in the D minor pentatonic scale - ie a Flat 3 chord (F major), and a Flat 7 chord (C major).

It doesn't mean the whole piece is suddenly in D minor, we're still in D major (or perhaps we could say we're in "D"); and we're allowing the flat 3 and flat 7 chords.

lincolnblue

Thanks for that...glad to know my theory wasn't totally wrong!